Adding salt to water raises its boiling point but lowers its melting point. The sodium chloride ions dissociate in the water and form bonds with the water molecules. These bonds are stronger than the bonds between the water molecules themselves, so more energy is required by the water to break free into water vapour. Similarly,[…]
Science tip: Evaporation of water absorbs heat energy from the surroundings. The full explanation is out of syllabus but for those interested, you can read up on latent heat and enthalpy of vaporization. Similarly, melting of ice also absorbs heat energy. From past year’s PSLE: Some buildings use a cooling mist system 2 lower the[…]
Science tip: qn: "my gal asked if evaporation will be faster with wind. I answered "Yes" but am stuck when we have to explain why?" ans: When water evaporates, the water molecules are released into the air. Water molecules can also go back from the air into the water. When humidity is at 100%, the[…]